A temperature color mapping of the effects of a closed Bering Strait. The northern Pacific cools while the northern Atlantic warms significantly enough to bully Norther American climate. (Source: Nature/UCAS)

The unassuming 53 mile Bering Strait hardly seems like the type of geological formation that would cause this kind of trouble. (Source: Wikipedia commons)

It comes down to one little strait and some really big sheets of ice.

The
Bering Strait, spanning a distance of approximately 53 miles between
Alaska and Russia, looks like an unassuming place for temperature
regulation for the entire North American region (including
Greenland), but recently published NCAR/UCAR findings seem to
indicate that it may be very geologically important.

The
strait serves as a gate for cooler, less salinized water from the
Pacific to flow to the warmer and saltier Atlantic. Their simulations
found that without this flow, the climate of North America fluctuates
much more rapidly – in the span of a few thousand years rather than
some tens of thousands – and helps explain constant temperature and
ice sheet modulation between 116,000 and 34,000 years ago, a time of
constant ice sheet advance and retreat.

In the past, this
pattern was often attributed to the Earth’s position along its
95,000 year orbital pattern, but the NCAR researchers found that when
correlated with the temperature and ice data, the orbit could not
explain the rapid fluctuations. Instead, it occurred to them that
changes to the Bering Strait itself could have a large impact on the
entire region due to the changes it would bring to the Pacific and
Atlantic ocean currents. Their models indicate that a slight change
in the strait would adversely affect the meridional overturning
circulation, an ocean current which helps drive the Atlantic
tropics-to-polar heat pump.

In
the simulation, they show that around 110 to 115 thousand years
ago, the northern climate cooled sufficiently to create giant ice
sheets over the northern regions of North America and all of
Greenland. As these ice sheets sucked up water from the global
oceans, sea levels dropped by as much as 100 feet. Eventually a vast
amount of the strait was no longer able to pass water – the average
depth of the strait is 100 - 190 feet. The new land bridge cut off a
vast portion of the ocean flow between the Pacific and Atlantic.
This, in turn, caused the Pacific ocean to become even cooler and
cleaner, but allowed the now saltier waters of the Atlantic to push
the meridional overturning circulation into overdrive, warming the
regional ocean, North America and Greenland by as much as 1.5C over a
few thousand years.

Next, the regional warming caused the iced
sheets to melt over another few thousand years, returning the oceans
to their previous depth and reopening the Bering Strait. With the
Atlantic’s access to cooler and cleaner water from the Pacific
restored, the cycle started all over again.

These temperature
oscillations went on like a driver overcompensating for an icy road
fishtail until finally, around 34,000 years ago, the Earth’s
distance from the sun was so great that it literally froze the
fluctuation in place. About 10,000 years ago, the Earth had finally
gotten close enough to the sun again to warm up the northern
hemisphere to the point where the strait reopened slowly and the
temperature variations settled into a much more docile animal.

This
study helps to provide convincing data for two things: that a
significant change in something even so geographically small can
adversely affect the climate of an entire quadrant of hemisphere, if
not an even greater area, and that the planet has its own regulatory
devices to deal with such things. However, it remains to be seen how
long the cycle would have gone on if not for the fortuitous position
in the orbital cycle. Too, this study reflects nothing at all of
man’s influence on these climate systems in current times. The key
to understanding these things lies in first understanding the basic
driving forces behind climate systems and the NCAR study has shown us
how one such small system may operate.

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If mankind has an effect on climate change, why has the climate not changed more drastically since the Industrial Revolution? Obviously before then we produced very little air and water pollution, so we should see a large jump between 1800 and about 1950. But we don't. The earth's climate cycles haven't changed for thousands of years.

I'm all for lowering pollution and using our energy more effectively, but we need to stop using fear of climate change to drive this movement.

Everytime a government needs to distract people, sth happens...Bush was good at that, every time the democrats were in the news with sth, there was a terrorist threat...And now the earth will die... well... Not the earth, trust me ;). If anything, just us weak human beings.

Next, human beings will die if there is too drastic climate change (anthropomorphic or otherwise). Well, most of us anyway. Again, documented, as crops will fail due to heat, crop land will be lost to desertification, pests will increase in number and range, etc.

quote: actually the CO2 is making plants grow harder, it's not destroying the planet by heating it up

This comment makes no sense. What do plants growing harder have to do with destroying the planet. Of course plants need CO2, and more in the atmosphere will produce lusher plants, but the loss of cropland necessary to feed people vastly outweighs any gains in production. As well, any gains in production from CO2 will produce less nutritious plants requiring people to eat more to stay healthy:

" but the loss of cropland necessary to feed people vastly outweighs any gains in production"

Loss of cropland? Hardly. A warmer planet means much more cropland, and longer growing seasons too boot. Take a look at the Roman Warm Period, or the Medieval Climate Optimum. Both periods where the planet warmed a few degrees...and agricultural output boomed.

Fine, we'll grow in Canada, you say. Trading the Canadian prairie for the US is a bad deal. It gets less sun and has a shorter season. Yields are less. And the Canadian prairie will also be less productive than it currently is as global temps increase:

So, instead of spout off crap invented in your addled mind, do some research, and you'll learn that climate change, irregardless of human involvement is a serious threat to the food supply of the US and the world.

As for the mini ice age, did you even read the article? Obviously not, or you'd understand the mechanism how increasing world temperatures could make a local ice age in Europe and North America. Warming model predictions HAVE failed. They have been too conservative, and the predicted effects have been happening much more quickly than initially anticipated.

Just wait hotshot...u will see we are being pushed to be scared and pushed to pay more taxes over a problem that at this point is not a problem yet, secondly it isn't caused by humans but by the planets own seasons which we don't and also can't understand as we have no real weather data from before, what is it? 1850? (Yes, we can see global trends, but not really the weather. Although the trends already show these long term seasons). These seasons can be as long as the estimated existance of humanity (the Darwin way, not the christian ;)

But please stress out and pay all ur income to ur government for their "green tax" bs, stop consuming at all. U will most certainly be a planet saving hero...

Sorry about the apostrophes, hopefully Firefox will soon include a grammar checker along with it's spell checker. That's why I focused on science and not the humanities.

Their is still a lot of argument over what causes the most change. CO2, Methane, or what? I think we will find CO2 is not as big of a culprit as we've made it out to be. As your question points out, it is only recently that CO2 and temperature increase match up.

The focus on CO2 is (once again) politicians trying to overly simplify a complex issue. Banning CO2 may improve things, but I don't think it will "fix" anything (my opinion only).

Gasses are not the only way to effect the climate. For instance, deforestation also has an effect. I read somewhere the drought in Somalia was intensified by the deforestation on the west coast of Africa caused by farming. We've been farming a long time in a lot of places so multiple small changes globally can result in an overall global climatic shift. The question is, how much (if any)?

We've been luckily the last 1000 years in that we've had a (relatively) stable climate. It has allowed are ancestors to advance to our current state. Looking over geologic time that is not always the case. If the one lecturer I heard is correct, calm periods like the one we've enjoyed these past 1000 years are the exception, not the rule.

The fact is, we don't understand the earth's natural climatic processes enough. We have some good ideas, but the earth is a complicated thing. To try to figure our influence while also figuring out a "baseline" makes it harder. The highly polarized political environment makes it harder still.

You are correct that the Earth is a very complex system. It has lots of buffers and inherent randomness. It is impacted by numeorus cyclical patterns (orbit, precision, sun spots, magnetic field) as well as geological events that make prognostication difficult.

But that all supports the current theories of climate change. The buffers are getting full. Oceans are becoming more acidic as they absorb CO2 in the form of carbonic acid. Atmospheric CO2 as a percentage is way up in the last 150 years.

Why? Because we have uncorked a whole lot of stored carbon since the industrial age and have been ramping that production every year. The world appears to be able to absorb a lot of that, but the buffers are getting full. I personally think that the conservative thing to do would be to stretch-out the world's supply of fossil fuels and utilize them in a way that the Earth can better manage. It takes a long time for the oceans to precipitate all of that stored carbon out into inactive carbonate solids. It would also be nice to stop sending the nations wealth to the Middle East.

quote: But it used to be more than ten times that...and we never had runaway global warming.

It may have been ten times higher hundreds of millions of years ago, but it has never been above 270ppm as long as modern humans have existed. Life and the planet were so different back then as to be unrecognizable today. It's not comparable to today.

"Modern humans" haven't existed for the blink of an eye as far as the planet is concerned. Your comment is pointless. Plenty of other life existed on the planet when CO2 levels were 5 or even 10 times higher than today. In fact, those periods were the most fertile and ecologically diverse ones in the planet's history. CO2 is good for the environment.

Saying that we "can't compare climate" between the Devonian and today is just a way of sticking your head in the sand. The fact is that CO2 has never before caused runaway warming , no matter how high its been.

Porkie, thanks for making my point for me. Exactly, plenty of life existed when CO2 levels were higher, but not HUMAN life. As for the claim that the world was more fertile and diverse 200m years ago, back it up with cites. Temps on average were higher, Pangaea meant that temps were more evenly distributed and much of the land was covered in jungle. That's all well and good. The Amazon has the most diversity on the planet. However, jungle soil is among the poorest to grow in:

Correct with mcnabney; the reason for the limited change thus far is that most of the waste we've produced has been absorbed by buffers, which are now nearing their capacity.

A few posts up, it was stated that the argument shouldn't be if man has caused global warming, but how man effects it, which frankly, couldn't be more true. Yes, the planet will warm and cool on its own; the question with Climate Change [see below why thats a much more correct term then global warming] is how much effect has man had, and what effect Climate Change will have on man.

Now, Climate Change is an odd beast because of how dynamic the planet is; a few theories of how Climate Change would go, one of which I found interesting, was that Climate Change would cause a short-term cooling of the continental US and Western Europe, due to a disrutpion of warm weather patterns...[so yes, you COULD argue that the current cold spell is due to Climate Change]

quote: But that all supports the current theories of climate change. The buffers are getting full. Oceans are becoming more acidic as they absorb CO2 in the form of carbonic acid. Atmospheric CO2 as a percentage is way up in the last 150 years.

I agree that CO2 is a problem, but only a recent problem, and not the only problem. Methane is also an issue which has been influencing things long before CO2 joined in. And yes, the ocean buffers are getting full. (For those of you wondering what were babbling about, you can get an idea by looking at PH versus Alkalinity. Any salt water aquarist should be familiar with that.)

I know it's a touchy subject but we really do need to invest heavily in nuclear power. For all its problems, its solves so many more problems. And I too would be happy to not send our wealth overseas, especially to those that hate us.

Why? It's airborne plant food. It's also very good at preventing ice ages...a climate change event that we're overdue for, and one that could kill billions of people.

The only risk of CO2 is the silly belief that it can cause some positive-feedback cycle that would result in runaway warming, despite tons of evidence to the contrary. But then people WANT to believe CO2 is bad, to justify some misguided anti-consumption, anti-capitalist agenda.

I think your failing to see the main danger with our effecting the atmosphere.

In nature, change happens. Some don't survive it, most do. The trees that currently exist in the cold of northern Canada used to be here in Virginia. But as the earth warmed, they naturally migrated north to their present location. Change can even be good. The failure of one species to adapt to change provides an opportunity for other species.

In nature, rapid change is always bad. To much change to fast wipes out a huge number of species. Whole ecosystems collapse. Eventually things come back but it takes time.

The concern to me is will we cause change that is to fast for nature to adjust to without huge pain. Or we will we cause the temperatures to go higher than they normally would, or even colder.

To make this more "human", imagine this. Temperatures warm and suddenly areas that grew lots of food can't, and areas they couldn't now can. Do you not think that's going to be a source of conflict between the former 'haves' and the 'haves not'? What if Kashmir suddenly become incredibly productive? Do you think India and Pakistan wouldn't go at each other over it in order to feed their starving populations? And both have Nuclear weapons.

Again, change is. But if it changes to fast it can cause a lot of pain adjusting to it.

quote: But that all supports the current theories of climate change. The buffers are getting full. Oceans are becoming more acidic as they absorb CO2 in the form of carbonic acid. Atmospheric CO2 as a percentage is way up in the last 150 years.

The problem with this though is that as the water in the ocean warms, it will absorb less CO2. If increased amounts of CO2 are causing global warming, then the oceans should be releasing vast amounts of CO2 into the atmosphere and becoming less acidic.

If the oceans are becoming more acidic and the temperatures are rising, then something other than CO2 must be causing the increase in acidity. But if increased CO2 absorbed in the ocean is causing the rise in acidity then the oceans must be cooling. It is a given fact that as the temperature of water rises that the partial pressure of the absorbed gasses above the water will increase which means the gasses are migrating from the liquid phase( ocean ) to the gasseous phase ( air ). This will happen with all gasses that are normally absorbed in the water. If the global temperatures are rising then we should see a rise in O2, CO2, N2, Ar, Methane, Water Vapor, and any other gasses in the air while at the same time they are falling in the oceans. To behave otherwise would mean that global warming has the power to over-ride the Laws of Thermodynamics and Solubility of Gasses. The only way to force more gasses into the water would be to increase atmospheric pressure, which I haven't seen reported.

Another problem I see is when people talk about burning fossil fuels releases stored carbon into the atmosphere. That is true, but most will make it sound as though it somehow increases the amount of carbon on the Earth. Conservation of Mass says that matter is neither created or destroyed in a chemical reaction. So the amount of carbon that is on the Earth today, should be equal to the amount of carbon that was on the Earth millions of years ago. If the change of CO2 in the atmosphere is what causes global temperature change, then before the carbon was captured by the plants and stored underground as fossil fuels, then the Earth must have been many times hotter in the past, or if not much hotter than now, we should be frozen in a global freezer now because of all the carbon that has been captured.

Water vapor is a much stronger green house gas than CO2, and if you want to test that do a simple experiment. Go outside just after sunset on a clear night and then again on a cloudy night and see which night the temperature falls the fastest. What you will find is that on a clear night the temperature will fall very quickly, yet on a cloudy night the temperature falls slowly. The reason is the water in the atmosphere works like a blanket. If CO2 was any where near as strong a greenhouse gas then since it has increased almost 50% in the last few hundred years we should be cooking by now.

Just my simple observations interpeted with my knowledge of chemistry and physics. Doesn't mean I'm right, but I have never seen it explained away either.

Your argument sounds quite convincing , but I think there is a mistake in it.

You're right , that a higher temperature leads to worse solubility of any gasses in the water .So at a constant C02 conc. in the atmosphere , rising temperature leads to higher C02 output of the oceans and thereby to less acidic oceans.

But we are measuring C02 conc. in ppm that means relative C02 conc. in the atmosphere.So the solubility per Mol is worse at higher temperatures, but the acidity of the oceans is influenced by the relative C02 conc. --> the higher partial pressure of C02.So acidity can increase together with the temperature and be caused by C02 solved in the ocean as carbon acid although the solubility of all gasses gets worse with higher temperature.The oceans are not saturated yet. If it was, you would be right.I hope you can see my point. English is not my mothertongue.

Yes, that would be one variable that could drive the equilibrium into the aqueous phase. I will have to run some calculations to see how much affect a higher molar concentration would have on the partitioning between the gas and liquid phases.

quote: If mankind has an effect on climate change, why has the climate not changed more drastically since the Industrial Revolution? Obviously before then we produced very little air and water pollution, so we should see a large jump between 1800 and about 1950. But we don't. The earth's climate cycles haven't changed for thousands of years.

Our data and records are, at best, incomplete. Additionally, 150 years is a drop in the bucket compared to the time scales involved with serious climate changes.

quote: If mankind has an effect on climate change, why has the climate not changed more drastically since the Industrial Revolution? Obviously before then we produced very little air and water pollution, so we should see a large jump between 1800 and about 1950. But we don't. The earth's climate cycles haven't changed for thousands of years.

The truth is that the climate has changed since the industrial revolution. Average global temperatures have gone up. This correlates with the artificial increase in CO2, a known heat retaining gas, in our atmosphere. Now, correlation is not causation, but to claim that the temperature has not changed is untruth.

If you look very closely at most of the graphs that show rise in CO2 and rise in global temperatures you will see that temperature rise preceeds CO2 rise. This is because of an equilibrium effect in which rising temperature causes release of CO2 from the oceans. Rising temperatures cause rising CO2, simple chemistry and physics, unless climate somehow overrides the laws of physics and thermodynamics.